Russell Johnston was a Liberal, an internationalist and a Scot, and passionate for all of these causes. He joined the Scottish Liberal Party when it was still tiny, won a seat which Scottish Liberalism's most colourful figure had failed to capture before him, and held it through eight elections over more than 30 years. He supported the 1988 merger with the Social Democrats, on condition that the word "Liberal" should remain in the merged party's title. A nominated member of the European Parliament when the UK first joined the European Community in the 1970s, he stood for the European Parliament in its first direct elections. Later, both from the Commons, and after 1997 from the Lords (as Baron Russell-Johnston), he became a leading member of the Parliamentary Assembly of the Council of Europe, and was its president from 1999 until 2002.

Russell Johnston was born in Skye in 1932, and went to school in Carbost and Portree. He moved away to Edinburgh for university, where he refounded the university Liberal Club, and then became its president. After National Service in the Intelligence Corps he trained as a history teacher, teaching in Edinburgh while joining the executive committee of the Scottish Liberals, then in 1963 becoming a paid research assistant for the party. Johnny Bannerman, the Gaelic-speaking host of one of the most popular programmes on Scottish television, had stood for Inverness in the six previous general elections, without success; Johnston, a local in a constituency which then included Skye, was successful at his first attempt, in 1964.

He found himself a member of a very small parliamentary party, in which the Scots were a significant force – six of the party's 12 MPs from 1966 to 1970. Very much a Highlander, he made his Commons maiden speech in a kilt, focusing on the economic and social problems of the Highlands in general and his constituency – then the largest in territorial extent in the UK, stretching from the town of Inverness to the islands of Skye, Rhum, Eigg and Muck – in particular.

In 1966 he introduced a Home Rule Bill to the Commons, solidly opposed by both the Labour government and the Conservative opposition. He served on the Royal Commission on Local Government in Scotland from 1966 until 1969, but continued through that period and until its achievement after the 1997 election to argue for a Parliament for Scotland. But he was not in any sense a nationalist, sharply criticising the Scottish Nationalist argument for independence. He was leader of the Scottish Liberal Party from 1974 until 1988, defending its position as an autonomous entity within a federal party, and encouraging the development of a younger generation of members who reached out beyond the Highlands and Borders to capture seats in Fife and in the central Lowlands.

Like many a north-west Highlander, he enjoyed his whisky – though he also developed a taste for claret through his European visits. He was a keen photographer, wherever he went, and a committed postcard-writer from wherever he travelled to; I last saw him in the Lords Library 14 days ago, surrounded by written and unwritten postcards. He built up a substantial majority in his constituency over several elections, as he campaigned against what he saw as the neglect of Highland development; in 1983 he gained almost 50 per cent of the vote in a four-way contest.

Changing political conditions, as well as his frequent travels abroad, led to a close-run contest when he last fought the seat in 1992, which was made even more fraught when the helicopter sent to collect the ballot boxes from the islands crashed on the way, and the count had to await their delivery by ferry and van. He then gained the distinction of retaining the seat on just over 26 per cent of the vote, with his Labour, SNP and Conservative opponents all capturing over 20 per cent of the votes cast.

Russell Johnston as a young man was a superb speaker, who could move an audience to understand why Liberalism mattered. He won the Observer mace for the best student debater in Britain in 1961. In the 1960s and 1970s he would attract packed audiences to hear him talk on Liberal philosophy in party conference fringe meetings, and sway conference members in debates on the floor. His soft Highland accent fitted his broad emphasis on political principles – liberty, local autonomy, social justice, international co-operation – which he contrasted to the narrowness of Scottish nationalism and the centralising statism of Labour and the Conservatives. In later life he published several collections of his speeches, by then predominantly on internationalism and European themes.

Starting from the same principles that led him to reject both British and Scottish nationalism, Russell Johnston became from the early 1960s an enthusiastic supporter of European integration. He was a committed federalist, both for the UK and for the European Community; he believed in the sharing of power among different levels of democratically accountable government, and saw no reason why this principle should stop at the water's edge. The cry "Where's Russell? Russell's in Brussels" was first used against him by his constituency opponents in the 1970s, when he served as a nominated member of the European Parliament, juggling travel schedules between Inverness, London and Brussels.

In later years he would quote this against himself, as he became progressively more engaged in the Parliamentary Assemblies of the Council of Europe and the Western European Union. After the end of the Cold War he was engaged in the Council of Europe's assistance to former socialist countries, and in its investigations of conflicts within the post-socialist world; like many others, he had attempted unsuccessfully to make Radovan Karadzic see reason.

His presidency of the Council of Europe Assembly was, in many ways, the high point of his later career. It came at a cost, in terms of constant travel, placing heavy strains on his family. It was in some ways fitting that he died while staying at his favourite hotel in Paris, after another European meeting which he had kept to, although already ill.